Field of the Invention
The present invention relates to wireless communication and, more particularly, to a method and an apparatus for setting a subframe for supporting MBMS.
Related Art
The Long Term Evolution (LTE) standard developed by the 3rd Generation Partnership Project (3GPP) is part of the Evolved-UMTS (E-UMTS) specification based on Evolved-Universal Terrestrial Radio Access Network (E-UTRAN). The LTE system employs Orthogonal Frequency Division Multiple Access (OFDMA) for downlink and Single Carrier-Frequency Division Multiple Access (SC-FDMA) for uplink. The LTE-Advanced (LTE-A) is an evolved version of the LTE system.
A system supporting the LTE/LTE-A standard transmits a reference signal and a control channel through a downlink carrier. For example, a Cell-specific RS (CRS), Primary Synchronization Signal (PSS)/Secondary Synchronization Signal (SSS), Physical Downlink Control Channel (PDCCH), and Physical Broadcast Channel (PBCH) are transmitted. The standard specification defines in which way the reference signals and control channels are allocated and transmitted through carriers.
In a future wireless communication system, a new type of carrier may be introduced, which transmits only part or none of the aforementioned reference signals and control channels. This feature is intended to improve an interference problem among a plurality of cells and to improve scalability among carriers. A new carrier having the feature above is called an extension carrier or a New Carrier Type (NCT).
Meanwhile, the LTE/LTE-A supports Multimedia Broadcast Multicast Service (MBMS). In the prior art, the MBMS is specified based on the channel structure and reference signal transmission with respect to existing carriers. However, since a channel structure and reference signal transmission different from the existing carriers can be used for the NCT, it may be difficult to apply the existing MBMS method to the NCT in the same manner.
Therefore, a method and an apparatus for the NCT to support the MBMS are needed.